JP2644879B2 - Direct acting rotary servo valve and rolling mill using the same - Google Patents

Description

The present invention relates to a direct-acting rotary servo valve and a rolling mill using the rotary servo valve.

[Conventional technology]

As a conventional rotary servo valve, Japanese Utility Model Laid-Open No. 63-5397
2. Description of the Related Art A direct acting rotary servo valve as described in Japanese Unexamined Patent Publication No. 2 (Kokai) No. 2 is known. The direct acting rotary servo valve includes a valve element rotatably provided in a casing, a disk-shaped rotor (movable element) integrally connected to the valve element and driven by a drive command. , And a stator, and a space between the stator and the rotor (movable element) is filled with a viscous fluid. The viscous resistance of the viscous fluid attenuates movable parts such as a rotor (movable element) and a valve element.

[Problems to be solved by the invention]

In the above prior art, it was very advantageous to use a method of filling the space between the stator and the mover with a fluid and providing damping by viscous resistance. In other words, in addition to being simple, the viscous resistance of the fluid also exerts an attenuating effect in directions other than the normal direction of motion, so that the space around the mover, which is the weakest in mechanical strength among the movable parts, is filled with the viscous fluid. Thereby, it is possible to protect the movable element from damage due to disturbances such as vibration and impact.

However, since the viscous resistance of the viscous fluid changes depending on the temperature, there is a problem that the damping characteristic changes during use due to the heat generated by the driving power supply and the driving means. In particular, when a high-speed response is required for the movable part (valve element), a larger driving energy is required because the resistance force applied to the mover by the viscous resistance is proportional to the speed of the mover. The heat generated by the driving means increases, and the attenuation characteristics become more unstable.

Further, even when the inertial load of the movable portion is large, a large amount of driving energy is required. Therefore, the size of the driving power supply and the driving means increases the amount of heat generation, which may cause unstable damping characteristics.

Furthermore, when it is intended to apply damping only to a viscous fluid as in the prior art described above, fine adjustment of the amount of attenuation or characteristics cannot be performed, and the servo valve has an optimal damping characteristic for use conditions. I couldn't let it.

Furthermore, when the above-described servo valve whose damping characteristic changes is used in a rolling mill, the rolling state becomes unstable,
It becomes difficult to process the thickness of the rolled material to a desired value.

Therefore, an object of the present invention is to provide a direct acting rotary servo valve that can stably maintain an optimal damping characteristic.

Another object of the present invention is to provide a rolling mill capable of maintaining a stable rolling state.

[Means for solving the problem]

The direct acting rotary servo valve of the present invention comprises a casing,
A valve body rotatably provided in the casing and configured to supply and control a pressurized fluid from a fluid source to a control object, a stator fixed in the casing, and a drive unit integrally connected to the valve body and driven by a drive command. In the direct-acting rotary servo valve comprising a driven mover and filled with a viscous fluid between the stator and the mover, a cylindrical hole that penetrates the valve body in an axial direction, An outer diameter and a concentric sleeve having an outer diameter equal to the inner diameter of the cylindrical hole forming a control orifice between the cylindrical hole of the valve body and the casing; a means for detecting an angular velocity of the valve body; Control means for comparing a signal with a target value and for giving a drive command to the mover based on the deviation thereof so as to attenuate the movement of the valve element.

Further, the rolling mill of the present invention controls the high-pressure working fluid supplied from the fluid pressure source to the reduction jack by the above-described direct-acting rotary servo valve of the present invention, and controls the rolling load applied to the rolled material. .

Hereinafter, the direct acting rotary servo valve may be simply referred to as a direct acting servo valve.

[Action]

A cylindrical hole provided in the valve body and penetrating in the rotating axial direction and an outer diameter and a concentric sleeve equivalent to the inner diameter of the cylindrical hole provided in the casing are arranged so that the opening area of the control orifice changes by relative movement. To control the flow of the pressure fluid.

By adopting the structure of the valve body as described above, the structure of the valve body is simplified, and particularly, the thickness can be reduced, so that the size and weight can be reduced. Therefore, it is possible to cause the movable portion (valve element) to respond at high speed with small driving energy, and it is possible to suppress a change in viscous resistance (damping characteristic) due to a temperature rise.

The control means for comparing the angular velocity of the valve body with the target value and attenuating the movement of the valve body based on the deviation compensates for the change in viscous resistance (damping characteristic) caused by the heat generated by the drive power supply and the drive means. I do. Further, it is possible to optimally adjust an attenuation amount or a characteristic that cannot be adjusted by viscous resistance according to use conditions.

As described above, it is possible to provide a direct acting rotary servo valve capable of stably maintaining the optimal damping characteristic.

Further, by using a direct acting rotary servo valve having such stable damping characteristics in a rolling mill, the rolling mill can maintain a stable rolling state.

〔Example〕

Prior to describing the embodiments of the present invention, the principle of the present invention will be described. The present invention provides a method of applying damping by viscous drag of a fluid, which is a method of directly applying a damping force to a movable portion. Since the damping method is a method that purely changes the characteristics of the control system, the damping force that acts as a resistance does not directly act on the movable part, and the damping effect due to the viscous resistance of the fluid is a method other than the normal movement direction. Is also based on the property of exhibiting a damping effect.

Therefore, in the present invention, the damping effect by the velocity feedback is added to the damping effect by the viscous resistance of the fluid, and the damping effect by the viscous resistance of the fluid protects the mover mainly against disturbances such as vibration and impact. This is used to obtain a vibration damping effect for reducing the vibration of the movable part, and the velocity feedback method is mainly used as a method for imparting damping in the normal direction of movement of the movable part. By doing so, the viscosity of the viscous fluid filling the space between the stator and the mover can be reduced, so that the resistance directly acting on the movable part is reduced, and the loss of the driving force due to the damping is reduced. As a result, the required driving energy can be reduced.

That is, the block diagram from the input signal e _i to the output fluid Q is the first diagram when only the viscous resistance of the viscous fluid is used.
As shown in the figure, when the velocity feedback of the movable portion of the servo valve is added thereto, the state becomes as shown in FIG.

Comparing these damping terms, in the latter case, the effect of velocity feedback, that is, the velocity feedback gain G _V is added, so
That much of the viscous damping coefficient c ₂ by the viscous resistance of the fluid it can be seen that can be made smaller than the viscous damping coefficient c ₁ in the case of using only the damping effect due to the viscosity of the viscous fluid. That is, the viscosity of the viscous fluid filling the space between the stator and the mover can be reduced. Accordingly, the resistance force cx directly acting on the movable part is reduced in proportion to the viscosity of the viscous fluid and the speed of the movable part, and the driving force F can be used more effectively.

Therefore, the relationship between the resistance cx due to the viscous resistance of the angular velocity omega and fluid when causing the movable portion displaces the x = a · sinωt is as shown in FIG. 3, for example, required for driving to the angular velocity omega _a driving force is reduced to F ₀ 'from F _0, or drivable angular velocity by the driving force F ₀ is increased from omega _a to omega _b. That is, the driving energy can be reduced by the area indicated by the diagonal lines in FIG.

Moreover, in the present invention, as a method of imparting damping in a normal motion state, a method of damping effect by speed feedback is mainly used, and a portion dependent on the speed feedback gain rather than a portion Rc ₂ depending on the viscous resistance of the fluid is used. As K _f G _A・ G _V becomes larger,
Since the viscosity of the viscous fluid and the velocity feedback gain are set, it is possible to obtain a greater driving energy reduction effect.

Accordingly, as a result of the loss of the driving force being reduced, the driving energy is reduced, and the driving current is increased. Problems such as an increase in heat generation, an increase in the size of the control device, and difficulty in obtaining high responsiveness are eliminated.

In addition, since the viscous resistance of the fluid exerts an anti-vibration effect against disturbances in all directions, it can sufficiently withstand mechanical disturbances such as vibration and impact, and it is movable especially to prevent damage due to disturbances Since there is no need to reinforce the armature, the armature can have a light structure, and the inertial load on the movable portion can be reduced. Accordingly, this also makes it possible to reduce the driving force loss and the driving energy.

In addition, since the damping characteristics can be set electrically, it can be easily adjusted to the characteristics suitable for the use conditions, and even if the viscosity of the fluid changes with temperature, the damping characteristics hardly change, so it is always stable Characteristics can be obtained.

Further, since the viscous fluid filling the space between the stator and the mover may be a fluid having a low viscosity, the fluid can be circulated, and if heat exchange is performed in the circulation path, the heat generated by the driving means Can be efficiently released to the outside, so that the temperature rise can be further suppressed.

Generally, the output signal of the speed detector is used as the speed signal used for the speed feedback.However, if a signal obtained by differentiating the output signal of the displacement detector is used, the speed detector becomes unnecessary, and the structure of the servo valve is reduced. In addition to simplicity, a signal line for speed feedback is not required, so that the system configuration can be simplified and higher reliability can be realized.

An embodiment of the present invention will be described below with reference to FIGS. 4 to 10. This embodiment shows an example in which a position servo system is configured using a direct acting servo valve.

 First, the structure and operation of the servo valve body will be described.

The valve body 1 is sandwiched by casings 2 and 3 together with a spacer 4 formed to be thicker than the valve body 1 by a predetermined thickness difference, and is provided rotatably. In addition, valve element 1
A disk-shaped movable element 6 is integrally connected to a shaft 5 that protrudes from the end face and penetrates the casing 3.

The valve body 1 is provided with a cylindrical hole 7 and a through portion 8, while the casings 2 and 3 are formed with an outer diameter equal to the inner diameter of the cylindrical hole 7 of the valve body 1, and And sleeves 9 and 10 provided concentrically with each other, and channels 11, 12 and 13 and 14 configured to be separated from each other by the sleeves 9 and 10, respectively.
Are configured to communicate with each other. In the casing 2, a control port is provided at the inner diameter of the sleeve 9.
15, a supply port 16 is connected to the flow path 11, and a discharge port 17 is connected to the flow path 12.

Therefore, as shown in FIG. 6 and FIG.
When the inner edge of the sleeve 9 and the outer edge of the sleeves 9 coincide with each other, the control port 15 is separated from both the supply port 16 and the discharge port 17, so that the flow of fluid stops and the state becomes neutral. As shown in FIG. 9 and FIG.
Is displaced in the direction of the arrow, a control orifice surrounded by the inner edge of the cylindrical hole 7 and the outer edges of the sleeves 9 and 10 and the inner and outer edges of the flow paths 11 and 13 is opened, and the fluid is supplied to the supply port 16.
To the control port 15. When the valve element 1 is displaced in the direction opposite to the arrow, the fluid flows from the control port 15 to the discharge port 17. That is, a three-way valve that is continuously variable in the forward and reverse directions is configured.

On the other hand, the mover 6 is rotatably narrowly provided at a predetermined interval by a casing 3 which also serves as a magnet 18 and a yoke. As shown in FIG. 10, a plurality of windings 19 are provided on the mover 6 so that the winding direction is alternately changed in the circumferential direction at every angle α. Are also configured so that various polarities alternate in the circumferential direction for each angle α. The valve element 1 and the mover 6 are supplied such that various boundaries of the winding 19 and various boundaries of the magnet 18 are shifted from each other by an angle α / 2 in a neutral state of the valve portion. Therefore, when an electric current flows through the winding 19, the electromagnetic force generated at each pole acts so as to generate a moment in the same direction, and rotates the valve body 1.

Further, an angular displacement detector 20 and an angular velocity detector 21 are provided on the back of the magnet 18, and these detection axes are connected to the valve element 1.
And the mover 6.

Now, in order to perform the position control of the control target 22, the output signal 24 of the displacement detector 23 provided in the control target 22 is fed back as a main feedback signal and compared with the target value 26 in the control device 25. The servo valve is driven accordingly to control the interlocking of the actuator. However, in the direct acting servo valve of this embodiment, the output signal 27 of the angle position detector 20 is also fed back to control the position of the valve body 1. And an output flow rate proportional to the input signal is obtained. Then, a shaft seal 29 is provided in the casing 3 to separate and shut off the valve section side and the drive section side, and the space between the mover 6 and the stator, that is, the casing 3 and the magnet 18 is filled with the viscous fluid 30. . Furthermore, the angular velocity signal output by the angular velocity detector 21
28 is closed to form a closed loop, and speed feedback is performed.

However, when the mover is interlocked, damping is also given by the viscous resistance of the fluid. Therefore, in the present embodiment, the damping effect due to the viscous resistance of the fluid is mainly used to protect the mover against disturbances such as vibrations and shocks. The damping effect by feedback is used. That is, for the normal direction of motion, the damping effect due to velocity feedback is greater than the damping effect due to the viscous drag of the fluid,
The viscosity of the viscous fluid and the velocity feedback gain are set.

Therefore, according to the present embodiment, the viscosity of the viscous fluid 30 can be reduced by the amount of the damping effect due to the speed feedback.
The resistance acting directly on the mover decreases in proportion to the viscosity of the armature, and the loss of driving force decreases. Therefore, since the driving energy is small, the driving means can be small and the driving current can be small, and high responsiveness can be obtained. Also, the amount of heat generated from the driving means is reduced, and the control device can be small.

In addition, since the viscous resistance of the fluid has an anti-vibration effect of protecting the mover from disturbances such as vibration and impact, it is not necessary to reinforce the mover to ensure vibration resistance. Therefore,
Since the mover can have a lighter structure and the inertial load on the movable portion can be reduced, the required driving energy can be reduced.

In addition, since the attenuation characteristic can be set electrically, it can be easily adjusted to the characteristic most suitable for the use condition.
Even if the viscosity of the fluid changes with temperature, the damping characteristics hardly change, so that stable characteristics can always be obtained.

Next, another embodiment of the present invention will be described with reference to FIG. This embodiment is an example in which a position servo system is configured using a direct acting servo valve as in the above-described embodiment, but in this embodiment, the output signal of the angular displacement detector is used without using the angular velocity detector. Differentiation is used as an angular velocity signal.

That is, the output signal of the angular displacement detector 20 is
Is directly fed back as angular displacement signal 27 and
It is differentiated by 31 and is also fed back as an angular velocity signal 28. Other configurations are the same as those of the above-described embodiment.

Therefore, the same effects as those of the above-described embodiment can be obtained, and the structure of the servo valve main body can be simplified since the angular velocity detector is not required, and if the differentiator 31 is provided near the control device 25, Since the signal line for angular velocity feedback is not required, the configuration of the entire control system is simplified, and the effect of improving reliability is obtained.

FIG. 12 shows still another embodiment of the present invention. This embodiment is also an example in which a position servo system is configured using a direct acting rotary servo valve, but the method of positioning the valve body is different.

The mover 6 and the magnet 18 are connected via a torsion spring 32, and only the angular velocity detector 21 is provided on the back of the magnet 18. That is, when the movable element 6 and the valve element 1 are rotated by the driving force generated on the movable element 6, a torsional moment is generated in the torsion spring 32 to resist the torsion, and the moment of the driving force and the resistance moment balance. Since it stops at the position, the position of the valve element 1 is controlled by the current flowing through the winding 19. Therefore, the angular displacement detector is unnecessary, and if the output signal 28 of the angular velocity detector 21 is fed back, the same effect as in the above-described embodiment can be obtained.

Therefore, according to the present embodiment, the structure of the servo valve body is simplified because the angular displacement detector is not required, and the signal line for the angular displacement feedback is not required, so that the configuration of the entire system is simplified. Also, the effect that the reliability is improved can be obtained.

Next, another embodiment of the present invention will be described with reference to FIG.

In the present embodiment, in the direct acting rotary servo valve of the embodiment shown in FIG. 11, the viscous fluid 30 filled in the space between the mover 6, the casing 3 and the magnet 18 is circulated using the pump 33. So that the heat exchanger 34
Is provided. That is, the heat generated in the winding 19 on the mover 6 is sent out of the driving means using the viscous fluid 30 as a medium,
The heat exchanger 34 is configured to discharge this to the outside.

In the method according to the prior art, it was difficult to circulate the viscous fluid because the viscosity of the viscous fluid had to be large to some extent in order to obtain a sufficient damping effect, but according to the present invention, as described above, Since a viscous fluid having a small viscosity is sufficient due to the effect of the velocity feedback, it is possible to circulate in this way.

Therefore, according to the present embodiment, the heat generated by the driving means can be efficiently released to the outside, so that the temperature rise of the driving means can be suppressed low, and more stable characteristics can be obtained. Become.

The present invention can be applied to a device using a conical mover as shown in FIGS. 14 and 15.

As shown in FIG. 15, the driving means in this embodiment includes a conical mover 36 having a plurality of windings 35 configured so that the winding direction is alternately changed in the circumferential direction for each angle β.
Similarly, a magnet 37 configured so that the polarity alternates in the circumferential direction alternately at each angle β, and a yoke 38 having a conical surface are rotatably narrowed with a predetermined gap so that the valve portion is in a neutral state. In the configuration, the boundary of each pole of the winding 35 and the boundary of each pole of the magnet 37 are configured to be shifted from each other by an angle β / 2,
The operation is exactly the same as the case where the disk-shaped mover shown in the above embodiment is used.

Therefore, according to the present embodiment, the same effects as those of the above-described embodiment can be obtained.

The present invention can also be applied to a device using a cylindrical mover as shown in FIGS.

As shown in FIG. 17, the driving means in this embodiment includes a cylindrical mover 40 having a plurality of windings 39 configured so that the winding direction is alternately changed in the circumferential direction for each angle γ.
Similarly, the magnet 41 is configured so that the polarity alternates in the circumferential direction alternately for each angle γ, and the yoke 42 having a cylindrical surface is rotatably narrowed with a predetermined gap so as to be rotatable. In the configuration, the boundary between each pole of the winding 39 and the boundary between each pole of the magnet 41 are configured to be shifted from each other by an angle γ / 2,
The operation is exactly the same as the case where the disk-shaped or conical-shaped mover shown in the above embodiment is used.

Therefore, according to the present embodiment, the same effects as those of the above-described embodiment can be obtained.

Further, the viscous fluid 30 that fills the space between the mover and the stator, that is, the casing and the magnet on the drive side may be the same fluid as the working fluid in the hydraulic circuit. There is no need for the shaft seal 29 that separates and blocks the means side, and the structure of the servo valve body is further simplified. Further, if the viscous fluid 30, that is, the working fluid is returned to the return circuit of the valve section, heat can be radiated by the heat exchanger in the fluid pressure circuit without using the circulation pump 33 and the heat exchanger 34. Therefore, the configuration of the system is further simplified.

The embodiments of the direct acting rotary servo valve described above are examples of all three-way valves, but may be two-way valves, four-way valves or multi-way valves having more ports. In this case, the same effect can be obtained.

Next, FIG. 18 shows an embodiment of a hydraulic control system for a rolling mill using the direct acting servo valve of the present invention.

The rolling mill 63 is provided with a pressing jack 65 as a pressing means for applying a rolling load to the rolling material 64, and a hydraulic source 66
A direct-acting servo valve 69 is provided to adjust the working fluid to be supplied to and discharged from the press-down jack 65 to adjust the distance between the work rolls 67 and 68 to control the thickness of the rolled material 64 on the exit side. The direct-acting servo valve 69 is provided with a displacement detector for detecting the displacement of the movable part, and the space between the stator and the movable element is filled with a viscous fluid.

Now, a displacement detector 70 is provided in the screw-down jack 65, and the displacement signal 71 detected here is fed back to the control device 72 as a main feedback signal and compared with a target value 73, and according to the deviation thereof. The direct acting servo valve 69 is driven.
In addition, the output signal 74 of the displacement detector provided in the direct acting servo valve 69 branches into two before the control device 72, and one of the output signals 74 is directly taken into the control device 72 as a displacement signal to control the position of the valve body. The other is differentiated by the differentiator 75 to become a speed signal, which is then taken into the control device 72 and used to attenuate the movement of the servo valve movable section. However, since the viscous fluid fills the space between the stator and the mover of the direct acting servo valve 69 as described above, damping is also given by the viscous resistance. However, in the normal control state, that is, in the normal direction of movement of the movable part of the direct acting servo valve, the viscosity of the fluid and the velocity feedback gain are set so that the damping effect due to velocity feedback is larger than the damping effect due to viscous resistance. Is provided, and the viscosity of the viscous fluid is set to a value smaller by the damping effect due to the velocity feedback.

Therefore, according to the present embodiment, when the movable portion of the direct acting servo valve moves, the resistance force directly acting on the mover is small, so that the loss of the driving force is small and the driving energy is small. In addition, the driving power supply can be reduced, and high responsiveness can be obtained. Further, the amount of heat generated from the driving means is small, and the control device can be small. In addition, since velocity feedback is used as the main damping method, even if the temperature in the direct acting servo valve changes and the viscosity of the fluid changes, the characteristics of the system are hardly affected. Therefore, a stable rolling state can be always maintained, and a rolled product with stable quality can be obtained.

Further, in a rolling mill, since a very large impact force is generated particularly when the leading end of a rolled material is caught between work rolls, control means such as a servo valve is required to have sufficient vibration resistance to withstand this. However, according to the direct acting servo valve of the present embodiment, the viscous fluid filled in the driving means exerts an attenuating effect on disturbances in all directions. The durability and reliability of the valve are improved.

Further, although the control device is usually installed in a control room remote from the rolling mill main body, in the present embodiment, the speed is generated by the differentiator provided immediately before the control device, so that the control device is connected to the rolling mill main body. Main feedback signal between rooms
It is only necessary to provide a signal line for returning the displacement signal 74 of the servo valve movable portion and the signal line 71, and a signal line for speed feedback is not required, so that the system configuration is simplified, the cost can be reduced, and Reliability is further improved.

As described above, according to the direct acting servo valve of the present invention, the driving force loss due to the damping is reduced, and the driving energy is reduced. The current is small and high responsiveness can be obtained.

In addition, even when there is disturbance such as vibration or impact, a vibration-proof effect can be obtained by viscous resistance of the fluid, so that vibration resistance and durability are improved and high reliability can be obtained.

In addition, since velocity feedback is used as the main damping method, it is possible to electrically adjust operating conditions to the most suitable characteristics electrically, and even if the temperature changes, the viscosity of the viscous fluid changes. Even if it does, the attenuation characteristics hardly change, and stable characteristics can always be obtained.

Further, since the viscosity of the viscous fluid can be low, it is possible to circulate the viscous fluid, and if heat exchange is performed in the circulation path, the heat generated by the driving means can be more efficiently released to the outside, The temperature rise can be further suppressed.

Also, if the velocity signal is created by differentiating the displacement signal and temperature feedback is performed using this signal, not only the speed detector becomes unnecessary, but also the structure of the servo valve body becomes simpler,
Since a signal line for speed feedback is not required, the configuration of the system is simplified, and the reliability is improved.

As described above, according to the present invention, it is possible to obtain a highly reliable direct acting servo valve which is resistant to disturbances such as vibrations and shocks, has stable characteristics at all times, requires a small driving energy, and has a small driving energy. In particular, when applied to a hydraulic control device of a rolling mill, a highly reliable system can be realized, and a rolled product with stable quality can be obtained, and the cost of equipment can be reduced. Can also be obtained.

〔The invention's effect〕

According to the present invention, the structure of the valve body can be made small,
By providing damping means by angular velocity feedback of the valve body, in addition to damping means by viscous fluid,
A direct-acting rotary servo valve capable of stably maintaining an optimal damping characteristic can be provided.

In addition, by using a direct acting rotary servo valve having such stable damping characteristics in a rolling mill, the rolling mill can maintain a stable rolling state.

[Brief description of the drawings]

FIG. 1 is a block diagram from an input signal to an output flow rate when damping is given only by viscous resistance of a fluid.
The figure is a block diagram from the input signal to the output flow rate when using the damping effect due to the viscous resistance of the fluid and the damping effect due to the velocity feedback of the servo valve moving part. FIG. 4 is a view showing a difference in loss of driving force due to a difference in viscosity of a viscous fluid filling a space between them, FIG. 4 is a partial cross-sectional view showing one embodiment of a direct acting rotary servo valve of the present invention, and FIG. 7 is a perspective view showing the configuration of the direct acting rotary servo valve, FIG. 6 is a view taken along line AA of FIG. 7, showing a neutral state of FIG. 7, and FIG. 7 is a view taken along line BB of FIG. FIG. 8 is an AA line view showing the opening state of FIG. 5, FIG. 9 is an exploded sectional view of FIG. 8, and FIG. FIG. 7 is a plan view showing the structure of the drive means of the direct acting rotary servo valve shown in FIG. 7. FIG. 11 is a partial sectional view showing another embodiment of the present invention. FIG. 12 is a partial cross-sectional view showing still another embodiment of the present invention, FIG. 13 is a partial cross-sectional view showing another embodiment of the present invention, and FIG. FIG. 15 is a perspective view showing the configuration of the driving means in FIG. 14, FIG. 16 is a partial cross-sectional view showing another embodiment having a different shape of the driving means, and FIG. FIG. 18 is a perspective view showing the configuration of the driving means of FIG. 16, and FIG. 18 is a view showing an embodiment of a hydraulic control system for a rolling mill using the direct acting servo valve of the present invention. 1… Valve, 2,3 …… Casing, 6,36,40 …… Mover, 1
9, 37, 41 ... magnet, 20 ... angular displacement detector, 21 ... angular velocity detector, 30 ... viscous fluid, 31 ... differentiator, 34 ... heat exchanger.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-68504 (JP, A) JP-A-62-274105 (JP, A) JP-A-63-254206 (JP, A) 53972 (JP, U) Actually open 1986-131505 (JP, U)

Claims (5)

(57) [Claims] A casing, a valve body rotatably provided in the casing, for supplying and controlling a pressure fluid from a fluid source to a control target, a stator fixed in the casing, and a valve body. A direct-acting rotary servo valve comprising a mover integrally coupled and driven by a drive command, wherein a viscous fluid is filled between the stator and the mover; A cylindrical hole penetrating in the direction, a casing having an outer diameter and a concentric sleeve equivalent to an inner diameter of the cylindrical hole forming a control orifice between the cylindrical hole of the valve body and the casing, and detecting an angular velocity of the valve body. Control means for comparing the angular velocity signal from the means with a target value and, based on the deviation, giving a drive command to the mover so as to attenuate the movement of the valve element. Linear motion characterized by Rotary servo valve. 2. The casing has the valve body narrowed from both sides in the direction of penetration of the cylindrical hole, and is provided on one surface of the casing facing the valve body so as to be separated from each other by the sleeve and the sleeve. The direct acting rotary according to claim 1, wherein the sleeve has a control port connected thereto, and the flow path has a supply port and a discharge port connected thereto. Servo valve. 3. The valve body is separated by a through hole penetrating through the valve body in the direction of the rotation axis, and a surface of the casing facing the valve body and opposite to the surface where the sleeve is provided. 3. The direct acting rotary servo valve according to claim 2, wherein a second sleeve and a flow path facing the sleeve and the flow path are provided. 4. A direct acting rotary servo valve according to claim 1, wherein said means for detecting the angular velocity includes a speed gain adjuster. 5. A rolling mill comprising: a rolling jack for applying a rolling load to a rolled material; and a servo valve for adjusting a working fluid supplied to the rolling jack from a fluid pressure source, wherein the servo valve is used as the servo valve. A rolling mill using the direct-acting rotary servo valve according to any one of claims 4 to 7.